Aspects of the present invention are directed to a cooling circuit and, more particularly, to a cooling circuit for use in gas turbine bucket cooling.
The delivery of coolant to turbine rotor buckets or blades is an important issue in gas turbine design and, accordingly, many different systems and methods of accomplishing the delivery of the coolant have been proposed. As an example, U.S. Pat. No. 6,217,280 discusses the use of a closed loop cooling circuit in which coolant flows through a turbine rotor disc. Similarly, U.S. Pat. No. 5,226,785 discusses using an inducer and an impeller to deliver bucket cooling flow while U.S. Pat. No. 5,317,877 discusses running extracted air through a heat exchanger and delivering the air to a rotor through an annulus where the air is pumped up to the turbine bucket inlet using an impeller.
In any case, in current turbine bucket cooling systems, an amount of cooling air required to cool the turbine buckets is approximately 30%-40% of the total parasitic air flow for a given machine. Therefore, any advancement in turbine bucket coolant delivery methods can yield large improvements in the performance of the machine.